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Solar Eclipse Expedition 1780 / 1980

Samuel Williams, professor of mathematics and natural philosophy, led the first solar eclipse expedition in North America in 1780. He traveled to Penobscot Bay, Maine, which was behind enemy lines during the American Revolution. The expedition was endorsed by Harvard and the American Academy of Arts and Sciences and had the support of the General Court of Massachusetts. The General Court authorized the use of a state galley for the trip. The Board of War financed the expedition.

According to the published account in 1785, Williams took a 2-foot reflecting telescope by Short, magnifying 90x with a micrometer by Dollond (0002); a 1-foot reflecting telescope by Short, magnifying 55x (0053) with a Dollond micrometer (0059); an astronomical quadrant by Sisson (0061); an Ellicott clock (0070); a 4-foot achromatic telescope by Dollond, magnifying 40x; a 1-foot reflecting telescope by Nairne, magnifying 55x; and Fahrenheit's thermometer. (The whereabouts of the last 3 are unknown.) Although they are not mentioned in Williams's report, he likely took the Martin octant (0007) and Nairne azimuth compass (0095).

In 1980, 200 years after the eclipse, a group of Harvard students and curator Ebenezer Gay re-enacted the expedition to Maine. They took the above instruments, with the exception of the Short reflector of 1-foot focal length. They added a variation compass and dip circle by Nairne (0025, 0026), and surveyor's level by Martin (0068) in the belief that they were perhaps used in 1780.